The medical industry has begun to use more and more devices made from polymers, such as sterilization containers, proctoscopes, orthoscopes and neural scopes. Like other medical devices, polymeric devices must be sterilized before each use, and thus over their useful lifetime, the sterilization process is repeated many times over.
Typical sterilization processes include exposure to sterilants such as steam or ethylene oxide (C.sub.2 H.sub.4 O). Since exposure to steam is likely to deform a polymeric device, ethylene oxide is the sterilant most frequently used with polymeric devices. On the positive side, ethylene oxide is an excellent sterilant, but on the negative side, ethylene oxide is an extremely poisonous and highly flammable gas. Hospitals must either provide safe sites and procedures to conduct their own sterilizations using ethylene oxide or use a more expensive commercial sterilizing contractor.
Whether a hospital does its own sterilizing or uses a contractor, polymers, due to their low density, tend to absorb and retain ethylene oxide. The greater the number of sterilizations, the greater will be the amount of residual or absorbed ethylene oxide in a particular polymeric device.
The Federal Food and Drug Administration (FDA) has written regulations that delineate the maximum allowable amounts of residual ethylene oxide. Current FDA regulations restrict residual levels to 250 parts per million (ppm) of ethylene oxide. Unfortunately, polymeric devices tend to exceed this maximum allowable level of residual ethylene oxide after only a few sterilizations. Thus, there is a need for a method to reduce the build-up of residual levels of ethylene oxide in polymeric medical devices.